1. Field of Invention
The present invention relates to a reflective mirror module. More particularly, the present invention relates to a reflective mirror module having adjustable reflective mirror.
2. Description of Related Art
In a projection apparatus, a reflective mirror used to change the light path is normally disposed on the inner wall of the housing of the optical engine in a fixed manner. However, as the angle at which the reflective mirror is placed has errors, the blue band phenomenon of the projected images occurs, which is solved by attaching mylar between the housing of the optical engine and the reflective mirror, or by adjusting the molds for manufacturing the housing of the optical engine to change the angle at which the reflective mirror is placed. However, these solutions normally require much time and cost.
Another solution is shown in FIGS. 1A and 1B, a conventional adjustable reflective mirror module 100 is installed on an optical engine housing 200. The reflective mirror module 100 includes a fixing support 110, a reflective mirror 120, a spring 130, a gasket 140, a fixing screw 150, and a plurality of adjusting screws 160. The fixing support 110 has a fixing groove 112 for fixing the reflective mirror 120 and a screwing portion 114 at the bottom. The screwing portion 114 of the fixing support 110 passes through the through holes 202 of the optical engine housing 200, and is exposed outside the optical engine housing 200. The fixing screw 150 is secured in the screwing portion 114 after passing through the gasket 140 and the spring 130, so as to fix the spring 130 between the position rib 206 of the optical engine housing 200 and the gasket 140. The adjusting screws 160 are screwed in the threaded holes 204 of the optical engine housing 200. By screwing the adjusting screws 160 into or out from the threaded holes 204, the angle at which the reflective mirror 120 is placed is adjusted.
However, when the conventional reflective mirror module 100 is assembled, the threaded holes 204 and the position rib 206 have to be added to the optical engine housing 200. Normally, the threaded holes 204 and the position rib 206 influence the molding process of the optical engine housing 200. Therefore, it is quite difficult to design and manufacture the reflective mirror module.